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Pathology and Laboratory Medicine
Test Catalogue

​Direct Antiglobulin Test

Transfusion Medicine

​Specimen Requirements​

  • ​Whole blood
​Required Volume


  • ​Optimal Volume: 4 mL
  • Minimum Volume: 1 mL
    (Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.)
  • Capillary Volume (Lavender Microvette (EDTA) only): 0.5 mL

Referred in:

  • ​Store at 2-8˚C up to 72 hours
  • Must be received in Transfusion Medicine within 72 hours of collection
Grounds for Rejection​


Referred in:

Testing Information​ ​



  • RUH on site testing available 24 hours/7 days
  • SCH on site testing available 0730-1530 Monday through Friday, excluding statutory holidays and bank days. After hours (1531 through 0729 hours) testing referred to RUH.
  • SPH on site testing available 0730-1730 Monday through Friday, excluding statutory holidays. After hours (1931through 0729 hours) testing referred to RUH.


  • On site testing available 0700-1730 Mon-Fri, 0800-1600 weekends/stats, call-back after hours

Referred in:

  • Not performed in local laboratory. Collected specimens must be sent to Saskatoon for testing.
Results Reporting​


  • Saskatoon/Humboldt – within 24 hours of receipt in Transfusion Medicine
  • Referred in – within 48 hours of receipt 


  • Saskatoon/Humboldt – within four hours of receipt in Transfusion Medicine
  • Referred in – not available


  • Saskatoon/Humboldt – within one hour of receipt in Transfusion Medicine
  • Referred in – not available
​Reflex Testing
  • ​Positive results (excluding newborns and neonates) will be tested with individual monoclonal reagents to determine if red cells are sensitized with C3d (complement), Immunoglobulin (IgG), or both
    • C3d testing unavailable in Humboldt
  • ​Tube test performed with polyspecific reagent containing both anti-C3d and anti-IgG
​Clinical Interpretation
  • ​Negative – no IgG or complement (C3d) detected on the surface of the red cell
  • Positive – IgG and/or complement (C3d) is present on the surface of the red cell
  • For neonates the Direct Antiglobulin Test (DAT) results do not always correlate with symptoms of clinical jaundice
​Specimen Retention
  • ​5 weeks, however additional testing should be performed within 72 hours of collection
Alternate Test Names​
  • ​Coombs test
  • DAT
  • Direct Coombs
​Additional Comments
  • ​Do not centrifuge
SHR LIS Test Code​
  • ​BBSPC (For Laboratory Use Only)

Test Ordering Requirements​ ​

​Forms Required

​Saskatoon/ Humboldt: 

Referred in:

Patient History​ ​

​Relevant Clinical History
  • ​Diagnosis
  • Recent transfusion and pregnancy history
  • History of hematopoietic progenitor cell or organ transplantation
​Relevant Recent Medication History
  • ​Recent medication history (the Medication Administration Record – MAR may accompany the Test Request Form)
  • The MAR need not be sent routinely with the test request, but will be requested by phone when needed


​If you choose to print this information, it is valid only on date of print.

Laboratory Controlled Document LSM-45 v4

Last Modified: Tuesday, August 20, 2019 |
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